2006 VW Beetle Convertible 2.5

Looking for a reason the Bug will randomly die while driving at slower speeds and with more consistency when the gas tank is between 1/4 and 1/2 full. Also when filling the tank, it requires pumping the pedal and 3 to 4 tries to get it to start. I was told to buy a new gas cap and did, but it didn’t resolve the issue. I recently had our mechanic look at it and he cleaned off the fuel canister and suggested that this part may need to be replaced—about $700. He indicated that it was heavily covered in sand. We know the car came from California. Any ideas?

My 2000 New Beetle Diesel required this for it to run like it had some jazz to it once again: clean the intake manifold, replace the EGR valve (can be 2nd market) and then replace the Mass Air Flow Sensor which is the main engine control . . . made all the difference. Before the work it went up this one hill only by down-shifting into 2nd. With the EGR valve, seal and gaskets replacement it got to 50mph on the same hill. My fantastic mechanic (Tim Haddad at Progressive Auto in Bainbridge, NY) thought there might be more, did some research, replaced the MAF Sensor (original equip. Bosch) and it went up the same hill at 70+ . . . . well worth what charges were. Replaced the fuel and air filters (always) and now it’s getting about 50 mpg on diesel fuel. Hope this helps you!